Installation of electric apparatus



Dec. 4, 1928. 1,694,288

E. G. SOHLBERG INSTALLATION OF ELECTRIC APPARATUS Figl.

Invenfor Erik G. Sohlberg, b5

Hi5 ATTorne vision of means l atented Dec. 4, 1928.

UNITED STATES PATENT OFFICE.

ERIK G. SO HLBERG, OF SCHENEGTADY, NEW YORK, ASSIGN OR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INSTALLATION OF ELECTRIC APPARATUS.

Application filed February 24, 1927. Serial No. 170,641.

My invention relates to installations of electric apparatus which is normally subjected to relatively large potential differencesand which is arranged in a number of separate fire-proof compartments for the purpose of localizing trouble in the event of a fault such as an insulation breakdown or failure in any part of the apparatus. In installations of this character as heretofore constructed ithas sometimes happened that upon a fault occurring in one compartment the trouble was not confined to that compartm'ent but has spread, by conducting gases orvapor, to other compartments and even toa'pparatus located a considerable distance away. .Such gases due to an are at one point have been known to cause an insulation breakdown and the starting of another are at a point more than 50 feet away.

It is an'object of my invention to provide means which will operate automatically to prevent faults being spread in such a way. Another object ofmy invention is theprofor the rapid ventilation of a compartment in which a fault occurs while at the "same time preventing the spread of trouble to apparatus in other compartments. These and other objects of my invention will appear from the detailed description which follows;

In accordance with one embodiment of my i'nventionl arrange the electric apparatus in chamberh or rooms having inlet and outlet ventilating openings. One set of openings, either inlet or outlet, I connect by a common duct with some device for moving the air. Iprovide electric means for separately opening and closing those openings in the several chambers which connect with the common duct? In the chambers I arrange devices which respond to a dilution of the air therein with conducting material and connect them with means controlling the openings so that when the device in any chamber operates, .the ventilation openings thereof remain open but the Ventilation openings to the common duct of all other chambers are automatically closed. I also provide means, responsive to the operation of any device, which tends to cause an increase in the amount of air being moved in the ventilating system if the system is already in operation and to start the system operating if it is shut down at the time the device operates.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

ing arranged on separate floors of the build-' mg. In the drawing I have shown but three main rooms or chambers 2, each of the same construction and housing similar apparatus. Communicating with these chambers is a common air duct 3 through which in the present instance air is withdrawn from the several chambers for the ventilation of apparatus therein contained. Each main chamber or room is shown having inwardly extending walls 4.; forming smaller chambers or cells 5 closed at the front by doors 6. In the respective cellsof each main chamber I have shown by way of example a reactor 8, a potential transformer 9, a fuse 10, a cur rent transformer 11, an isolating switch 12, and an oil switch 13 connected to the phase bus bar 14:. From the reactor 8 the circuit connect-ion is shown carried through a duct 15. I have indicated a common operating mechanism 16 for the three isolating switches and also for the three oil switches located on the floor above the main chambers and connected with the several switches by means of the rods 17 arranged in a vertical shaft adjacent the main chambers.

For the ventilation of the apparatus I have shown the doors 18 which lead into the chambers from the outer hall 19 of the building provided with louvers 20 and the doors 6 which close the cells of each chamber also provided with louvers 22. The louvers preterably open inward or toward the apparaa tus and are gravity closed whereby in the event of a sudden gas formation in any part of the apparatus, the louvers controlling the opening leading thereto are held firmly closed. Each chamber is shown having two separate outlet openings controlled by the louvers which normally remain open. Movement of the air through the chambers may be effected by connectin the duct 3 with a suitable stack, but preferably 1 employ a motor-driven exhausting fan shown in Fig. 1 as located on the top floor of the building and connected with the duct 3 by pipe 26. The duct 3 as has already been pointed out common to the chambers 2 on all three floors receiving air passing the several louvers 2% of the outlet openings of the chambers. A similar set of chambers having similar ventilating openings and arranged on the opposite side of the duct may be served by the same duct as indicated on Fig. 1 if desired and obviously various extensions of the ventilating system herein disclosed may be made to suit Various conditions. Where the duct 3 passes the floors of the building I have shown gratings 27.

For driving the fan I have shown the shunt motor and control apparatus therefor which comprises the switch 31 having operating solenoid 3'2 and latch 33, field rheostat as with arm 35, operating motor 30 therefor having opposed field windings 57 and 8S, limit switches 39 and and the manual control switch ll for the motor 36, energy for the above apparatus being taken from the supply circuit 42. To start the fan motor 30 the switch 41 is closed by pushing it inwardly. Motor 36 immediately starts movement of rheostat arm 35 which in turn closes the field circuit of motor 30 and the circuit of the solenoid 32 whence motor switch 31 closes and latches and the fan motor begins rotating. As the movement of the rheostat arm continues more and more of the rheostat 34 is cut out of the motor field circuit and the fan motor speeds up until finally the arm reaches the end of the rheostat and operates limit switch 10 to stop motor 36. Automatic means may be employed for returning the arm 35 to its initial position whenever the fan motor is stopped. This may also be done manually by the apparatus illustrated by pulling out the switch 41 to close the circuit of motor 86 through winding 87 whence the motor is operated in the reverse direction until limit switch 39 is opened. If it is desired to operate the fan at some speed less than its full speed the switch 31 may be closed by hand and switch 41 closed only long enough to bring the rheostat arm to the position necessary to give the desired fan speed.

The means which I have shown in the chambers for causing the operation of the means which control the ventilation of the respective chambers in response to a dilution of the air therein with conducting material are the spark gaps 45, preferably sphere gaps, three of which are shown in each chamber arranged in the cells above the apparatus therein and set to break down at a voltage slightly in excess of that to which they are subjected. Because of the difiiculty of setting these spark gaps so as to respond to the desired dilution of the surrounding air when they are connected to the usual auxiliary circuit of say 120 volts, I have provided transformers 1G to step up the voltage applied to the spark gaps. These transformers may be small and inexpensive and may for example give a stepped up voltage of say 5000 volts. Various arrangements of the spark gaps and the transformers may be made to suit the existing conditions. In the drawing 1 have shown two spark gaps in one chamber connected by leads 47 to the secondary side of one transformer and the third spark gap of the same chamber connected by leads 4:8 to a separate transformer. I may provide a separate transformer for each spark gap and locate it close to the spark gap thereby avoiding long leads in the secondary circuit. Should the installa tion be such that inflammable gases are generated or are present, as for example in a mine, the gaps may be covered with suitable screens to prevent ignition of the gases. The primary windings of the transformer l6 are connected respectively with the windings d9 of the relays 50, suitable connections being made to the auxiliary circuit 51. Each relay is shown having three sets of contacts, an upper, a lower, and an intermediate set. Connected to an upper contact of each relay is a solenoid 52 whose plunger by connection with the arm 53 operates the louvers 23 of one of the chamber out-let openings to close the opening when the solenoid is energized. The other upper contacts connect with the auxiliary circuit through the contacts of the relay A middle contact of each relay is connects with a. suitable annunciator 56 and a lower contact of all relays l8 connects jointly with an alarm signal 57, the winding of relay and with the winding of relay 58. The contacts of relay 58 connect by leads 59 with the rear contacts of switch ll.

ll' with the apparatus in the position illustrated, the ventilating fan being not running,

trouble occurs in the apparatus in any chamher as, for example, a short circuit to ground such that the air in a chamber or in a cell in a chamber becomes diluted to a predetermined degree with conducting material,

the spark gap 45 therein breaks down. The

resulting current flow in the primary of the transformer 46, this being relatively large on account of the ratio of transformation, is sufficient to actuate the corresponding relay 50. Such actuation opens the circuit of the solenoid 52 which controls the louvers 23 associated with the particular cell or cells containing the spark gap which broke down, hence these louvers remain open. The same relay actuation also causes the operat'on of one of the annunciators 56 which shows which relay has operated and hence where the location of the trouble and causes the operation of signal 57 and of relays and 58. Closing of relay 55 results in the closing of all louvers 23 except the one controlling the ventilation of the cell in which the trouble exists Clos ng of relay 58 starts the fan 25 running in the manner already described. The whole effort of the fan is thereby centered on the removalof air, gas, smoke, etc. from the cell or chamber in trouble which together with the fact that outlet openings of the other cells and chambers are now closed prevents the trouble from spreading to other parts of the installation.

It the fan is running at some reduced or intermediate speed and trouble occurs, the operation is similar. The louvers of all cells except the one in trouble close as before and the fan is quickly brought up to full speed. The louvers 20 and 22 open automatically with the air drawn into the cells and also close automatically when the current of air stops or if a sudden pressure develops in the cell. Should gas or other diluting material be developed outside of the cells and be drawn in through the intake louvers a breakdown of one or more gaps would occur as soon as the diluted air was drawn over the gap whereupon the effort of the ventilating system as before would be centered upon the chamber or cell affected and other chambers or cells would be isolated therefrom.

Upon a return of normal conditions in the chamber which was in trouble and a restoration of the spark gap or gaps which had broken down, relays 55 and 58 and the relay 50 which had operated will automatically return to their former positions whereby those louvers 23 which had been held closed will be reopened and the ventilation of all the chambers continue alike. This resto 'ation of the relays and louvcrs may also be effected, if desired, by'a momentary opening of the control circuit 49 by an operator it, for example, the spark gap which broke down continues to discharge after thetrouble has been removed, the annunc'ators 56 indicating which it any ofthe relays 50 are still operated.

lVhile I have illustrated my invention as appl'ed to an electric switching station of the isolated phase type where similar apparatus associated with the several phases are located in separate concrete rooms or chambers it is evident that my invention is'not limited to such a station, but is applicable to various other collective arrangen'ients of electric apparatus and to individual electric units where a lowering of the conductivity of the air or other medium due to trouble at one point is liable to cause a breakdown at another point. Accordingly I aim in the appended claims to cover such modifications and variations as fall within the true spirit and scope of my invention-and I use the term installation n the following claims broadly to include both groups of electric apparatus and a single piece of electric apparatus or unit.

hat I claim as new and desire 'to secure by Letters Patent of the United States is:

1. In an installation of electric apparatus, a structure comprising inter-communieating chambers, electric apparatus in said chambers, and means responsive to the presence of a predetermined amount of conducting material in the air in any chamber for preventing said air from escaping into other of said chambers.

2. In an installation of electric apparatus, a structure comprising a plurality of passage-connected chambers, electric apparatus in said chambers, passage-closing means and means responsive to the presence of a predetermined amount of conducting material in the air in any chamber for causing the operation of said passage-closing means associated with the other chambers whereby trouble in one chamber is prevented from spreading to another chamber.

3. In an installation of electric apparatus, a plurality of members adapted to be subjected to a relatively large potential difference, means providing a plurality of ventilating passages communicating with said members and means responsive to the presence of a predetermined amount of conducting material in the air in any passage for isolating said passage from the other passages.

4. In an installation of electric apparatus, a structure comprising chambers, electric apparatus in said chambers, and means responsive to the presence of a predetermined amount of conducting material in the air in any chamber for rapidly withdrawing air from that chamber.

5. In an installation of electric apparatus, a structure comprising-a plurality of cl'iambers, electric apparatus in said cham bers, common ventilating means for said chambers, and means responsive to the presence of a predetermined amount of conducting material in the air in any one chamber for isolating the other chambers from said common ventilating means.

6. In an installation of" electric apparatus, a structure comprising a plurality of chambers having ventilating openings and con-- taining electric apparatus, a common ventilating means for said chambers ar ranged to communicate with said openings, and means effective upon a predetermined increase in the conductivity of the air in any chamber for closing the ventilating openings of each of the other chambers.

7 In an installation of electric apparatus, a structure comprising a plurality of chambers havingventilating openings and containing electric apparatus, a common ventilating means in communication with said openings and means effective upon a predetermined increase in the conductivity of the air inany chamber for increasing the ventilation of-said chamber and for decreasing the ventilation of the other chambers.

8. In an installation of electric apparatus, a building structure comprising a plu 'ality of chambers and a ventilating passage having a connection with each of the chambers, electric apparatus in the chambers, spark gaps in said chambers and means controlled by the breakdown of a spark gap in any chamber for closing the connection between the ventilating passage and each of the other chambers.

9. In an installation of electric apparatus,

a building structure comprising av plurality of chambers and a i 'entilating passage having a connection with each of said chambers, electric apparatus in the chambers, means controlling the connection between said passage and each of said chambers, an exhausting i'an communicating with said passage, and means including spark gaps arranged in said chambers for controlling said means and the operation of said exhausting fan.

In witness whereof, I have hereunto set my hand this 23d day of February, 1927.

ERIK G. SOHLBERG. 

